1. Field of the Invention
The present invention relates generally to a slot bearing and more particularly to a floating slot bearing for providing a bearing surface between the slot walls and a carrier or other member moveable in the slot. The invention has particular application to rodless cylinders of the type having an elongated slot and a force transfer carrier bracket extending through the slot and moveable along the slot.
2. Description of the Prior Art
Various devices and apparatus exist in which a force or motion transmitting member extends through and is moveable along an elongated slot formed in a substrate or tubular member. One such device is a slotted type rodless pressure cylinder having a force or motion transmitting carrier bracket extending through the slot for transmitting the force or motion of an internal piston to an external workpiece. During this force or motion transfer, loads are imposed on the carrier bracket, the piston and the cylinder. Where the loads are balanced, the piston acts as the primary bearing, thus transferring the forces to the cylinder bore and cylinder wall. In conditions where the loads result in torsion or torque forces on the carrier, however, forces are created between portions of the carrier extending through the slot and the side edges of the slot. In these situations, slot bearings positioned between the carrier and the side edges of the slot are the primary bearing means.
In devices such as rodless cylinders described above which contain slot bearings, it is common for manufactures to securely attach or affix the slot bearings to the carrier in the region of the slot. Common methods for accomplishing this attachment include the use of pins, adhesives, machined recesses or grooves. These attachment techniques not only increase carrier manufacture time, but also, in many cases, weaken the structure of the carrier bracket itself. This is particularly true where portions of the carrier bracket need to be removed to form recesses, grooves or screw holes, to attach the slot bearings.
A device is also known in which holes are formed through the web of the carrier to receive corresponding pins integrally formed with bearing members. Although limited rotational movement of the bearing members relative to the web is permitted abut their respective pins, the formation of the holes increases manufacturing time and tends to weaken the strength of the web.
Accordingly, there is a need in the art for a slot bearing assembly and construction which minimizes the manufacturing cost and which also preserves the strength and integrity of the component parts, and in particular the carrier bracket.